Congenital fibrosarcoma of the ileum: case report with molecular confirmation and literature review

Intestinal infantile fibrosarcoma with translocation of NTRK. A case report and review of the literature

INTRODUCTION

Infantile fibrosarcoma is a rare non-rhabdomyosarcomatous soft tissue tumor (0.0005%) of which only 10% occur in the abdomen where they rarely affect the gastrointestinal tract. The median age at diagnosis is 3 months although 40% of them are present at birth.

MATERIAL AND METHODS

When infantile fibrosarcoma is diagnosed in our center, a clinical-pathological description is made together with a bibliographic review.

RESULTS

We present the case of a 6-day-old girl who presented with irritability and rejection of food. She was diagnosed with acute abdomen due to perforation and underwent surgery where a mass on the ascending colon was removed. Histopathology revealed a proliferation of spindle cells consisting of intertwined fascicles, infiltrating the adjacent tissues. Nuclear pleomorphism, few mitoses, foci of necrosis and hemorrhage are seen. Immunohistochemistry showed positivity for Pan-TRK and the NGS panel (Archer DX) demonstrated the TPR::NTRK1 fusion. No case with these characteristics, location or TPR::NTRK1 fusion were found in the literature.

CONCLUSIONS

Infantile fibrosarcoma is a very infrequent tumor which is exceptionally rare in the intestine. It is important to look for the characteristic genetic rearrangement of these tumors both to confirm the diagnosis and differentiate them from other pediatric spindle cell tumors and determine the correct targeted treatment. Selective TRK inhibitors have shown a 75% response rate in children and adults with tumors that exhibit TRK fusion. It was possible to find fusions with the Archer DX panel that the Oncomine panel did not detect.

Adult NTRK-rearranged spindle cell neoplasms of the viscera: with an emphasis on rare locations and heterologous elements

NTRK-rearranged mesenchymal neoplasms mostly affect the soft tissues of pediatric patients. Given the responsiveness to selective NTRK inhibitors, it remains critical to identify those ultra-rare cases occurring in the viscera of adults. In five females and two males aged 18-53 years, we characterized visceral mesenchymal tumors harboring TPM3-NTRK1 [uterine cervix (N = 2), pleura, prostate], LMNA-NTRK1 (lung), SQSTM1-NTRK3 (heart), and NTRK3 rearrangement with unknown fusion partner (colon/mesocolon) with RNA sequencing, FISH, RT-PCR, and immunohistochemistry. The tumors exhibited spindled to ovoid/epithelioid or pleomorphic cells, often arranged in fascicles, and were low-to-intermediate-grade and high-grade in three and four cases, respectively. Keloid-like stromal collagen and perivascular hyalinization was noted in five. Adenosarcoma-like appearances were observed in two, manifesting frond-like protrusions in one cervical tumor and phyllodes-like architecture in the prostatic tumor. Abrupt high-grade transformation into pleomorphic liposarcoma was found in another cervical tumor, while the pleural tumor contained intermixed rhabdomyoblasts. Pan-TRK immunostaining was positive in all cases. All cases expressed CD34, while five were S100-positive. CDKN2A homozygous deletion with concomitant p16 loss occurred in 4/7. Whole-exome sequencing identified TP53 mutation (c.672+2T>C, involving a splice site, with concomitant protein loss) in a cervical sarcoma, limited to its heterologous liposarcomatous component. At least moderate pan-TRK immunoreactivity was present in varying proportions of potential pathologic mimics, with BCOR-positive sarcoma (56%, 5/9), undifferentiated uterine sarcoma (50%, 3/6), and spindle cell/sclerosing rhabdomyosarcoma (33%, 2/6) being among the most frequent. This underscored the unsatisfactory specificity of pan-TRK immunohistochemistry and warranted molecular confirmation in the diagnosis of adult NTRK-rearranged visceral mesenchymal neoplasms. The current report highlights the ever-expanding clinicopathologic and genetic spectrum of this entity by describing the unprecedented cardiac and pleural locations and heterologous differentiation, as well as the second NTRK-rearranged "prostatic stromal sarcoma," while substantiating CDKN2A deletion as a frequent occurrence.

Mesenchymal tumors of the gastrointestinal tract with NTRK rearrangements: a clinicopathological, immunophenotypic, and molecular study of eight cases, emphasizing their distinction from gastrointestinal stromal tumor (GIST)

Mesenchymal tumors driven by NTRK fusions are clinically and morphologically heterogeneous. With an increasing number of clinicopathological entities being associated with NTRK fusions, the diagnostic and predictive value of the identification of NTRK fusions is uncertain. Recently, mesenchymal tumors in the gastrointestinal tract with NTRK fusions were described as gastrointestinal stromal tumors (GIST), but the nosology of such neoplasms remains controversial. We report eight mesenchymal tumors involving the gastrointestinal tract with NTRK1 or NTRK3 rearrangements. The tumors occurred in six children and two adults, five males and three females (age range 2 months-55 years; median 3.5 years), and involved the small intestine (n = 4), stomach (n = 2), rectum (n = 1), and mesentery (n = 1). Clinical outcomes were variable, ranging from relatively indolent (n = 2) to aggressive diseases (n = 2). Morphologically, the tumors were heterogeneous and could be classified in the following three groups: (1) infantile fibrosarcoma involving the gastrointestinal tract (n = 4), enriched for NTRK3 fusions; (2) low-grade CD34-positive, S100 protein-positive spindle-cell tumors, associated with NTRK1 fusions (n = 2); and (3) unclassified high-grade spindle-cell sarcomas, with NTRK1 fusions (n = 2). By immunohistochemistry, the tumors demonstrated diffuse pan-TRK expression, of variable intensity, and lacked a specific line of differentiation. Four cases expressed CD34, which was coexpressed with S100 protein in three cases. Expression of SOX10, KIT, and DOG1 was consistently absent. Molecular genetic testing identified TPM3-NTRK1 (n = 3), TPR-NTRK1, LMNA-NTRK1, and ETV6-NTRK3 (n = 2), and SPECC1L-NTRK3 in-frame gene fusions. We conclude that the evaluation of mesenchymal spindle-cell neoplasms of the gastrointestinal tract without a definitive line of differentiation should include interrogation of NTRK alterations, particularly in pediatric patients. Mesenchymal tumors of the gastrointestinal tract with NTRK rearrangements are clinically and morphologically heterogeneous, and few, if any, seem related to GIST.

A Case of Congenital Infantile Fibrosarcoma of the Bowel Presenting as a Neonatal Intussusception

Neonatal intussusception of the intestinal tract is rare. However, most neonatal intussusceptions have an organic lead point. For the lead point to be a neoplasm is extremely rare. We report a case that presented with neonatal intussusception with a congenital infantile fibrosarcoma as the lead point. The detection of ETV6-NTRK3 gene fusion was useful, although the definitive diagnosis was achieved by a comprehensive evaluation including this gene analysis, standard histology and immunohistochemistry. Neonatal intussusception should be suspected to be caused by a neoplasm. If pathological diagnosis is difficult, molecular analysis should be utilized to diagnose congenital infantile fibrosarcoma.

Congenital Infantile Fibrosarcoma Causing Intestinal Perforation in a Newborn

Congenital infantile fibrosarcoma (CIF) is a rare malignant mesenchymal tumor and only 14 cases have been reported with gastrointestinal manifestation. We report about a female newborn delivered per emergency cesarean section at 34 weeks of gestation. Postnatally, she rapidly developed an acute abdomen and sonographic evidence of intestinal perforation requiring laparotomy on the first day of life. A perforated 2 × 3 cm sized spherical tumorous structure of the jejunum was identified. Due to unknown histopathology at this point and unclear resectional margins, she received a temporary ileostomy, which was closed two months later. Histopathology revealed a congenital intestinal fibrosarcoma without the characteristic ETV6-NTRK3 fusion transcript. In conclusion, this rare tumor must be considered as differential diagnosis of intestinal perforations in newborns.

Congenital intestinal fibrosarcoma with rapid recurrence requiring adjuvant chemotherapy

A total of 16 cases of congenital fibrosarcoma have been reported from 1975 to March 2015. Five of the 16 had abnormal fusion between erythroblast transformation specific translocation variant 6 and neurotrophin recptor gene neurotrophic tyrosine kinase, receptor, type 3 (ETV6-NTRK3); in another five out of 16 this was absent, and six were not tested. All were managed by surgical resection but none involved metastasis. Herein we report the case of a newborn baby girl with congenital fibrosarcoma negative for ETV6-NTRK3 gene fusion, who presented with ileal perforation and positive resection margin. She had rapid recurrence with lymph node metastasis treated with postoperative chemotherapy. There was no further recurrence at >3 years of follow up.

Intestinal congenital/infantile fibrosarcoma: a new clinico-pathological entity?

Congenital/infantile fibrosarcoma (IFS) is a relatively rare form of fibrosarcoma diagnosed at birth or during early years of life and that differs from its adult counterpart because of a more favorable behavior. IFS is also known as cellular congenital mesoblastic nephroma, when it affects the kidney and is often but not always characterized by the ETV6-NTRK3 fusion transcript. We report herein the first series of an exceptional tumor of the small intestine occurring in newborns. The four patients shared a stereotyped clinico-pathological presentation with early and acute onset, intestinal perforation, and an infiltration by a highly cellular spindle cell tumor within the dilated intestinal wall exhibiting pathologic features typical of IFS. Molecular studies for the ETV6-NTRK3 translocation were negative in the three cases tested. Patients were treated by surgical wide resection alone and are alive and well (follow-up: 36 months-25 years). Thus, this new clinico-pathological entity, even with lack of documented evidence of the ETV6-NTRK3 translocation, should be included in the differential diagnosis of congenital bowel perforation or obstruction and may represent an intestinal counterpart of IFS.

Congenital fibrosarcoma of the bowel: sonographic description of a rare case of neonatal intestinal obstruction

A case of localization in the bowel of congenital fibrosarcoma (a rare soft-tissue tumor usually occurring in the extremities) causing intestinal obstruction in a newborn girl is described. A focal thickening of the ileal wall with features mimicking intussusception was identified at sonography; the final diagnosis was achieved by means of molecular analysis after surgical removal of the mass.

Molecular strategies for detecting chromosomal translocations in soft tissue tumors (review)

Approximately one third of soft tissue tumors are characterized by chromosomal aberrations, in particular, translocations and amplifications, which appear to be highly specific. The identification of fusion transcripts not only supports the diagnosis, but provides the basis for the development of novel therapeutic strategies aimed at blocking the aberrant activity of chimeric proteins. Molecular biology, and in particular, cytogenetic and qualitative and quantitative polymerase chain reaction technologies, allow with high efficiency and specificity, the determination of specific fusion transcripts resulting from chromosomal translocations, as well as the analysis of gene amplifications. In this review, various molecular techniques that allow the identification of translocations and consequent fusion transcripts generated are discussed in the broad spectrum of soft tissue tumors.